Stop ticking cycles as part of emitting the opcodes, we are counting

them externally in audio.py now.

Add some docstrings

transcoder/machine.py

@@ -8,29 +8,42 @@ import screen
 
 
 class CycleCounter:
+    """Counts clock cycles."""
+
     def __init__(self):
         self.cycles = 0  # type:int
 
     def tick(self, cycles: int) -> None:
+        """Advance cycle counter by some number of clock ticks.
+
+        :param cycles: How many clock cycles to advance
+        """
         self.cycles += cycles
 
     def reset(self) -> None:
+        """Reset cycle counter to 0."""
+
         self.cycles = 0
 
 
 class Machine:
-    """Represents virtual machine state."""
+    """Represents Apple II and player virtual machine state."""
 
     def __init__(self, cycle_counter: CycleCounter,
                  memmap: screen.MemoryMap, update_priority: np.array):
-        self.page = 0x20
-        self.content = 0x7f
+        self.page = 0x20  # type: int
+        self.content = 0x7f  # type: int
 
-        self.memmap = memmap
-        self.cycle_counter = cycle_counter
-        self.update_priority = update_priority
+        self.memmap = memmap  # type: screen.MemoryMap
+        self.cycle_counter = cycle_counter  # type: CycleCounter
+        self.update_priority = update_priority  # type: np.array
 
     def emit(self, opcode: "Opcode") -> Iterator[int]:
+        """
+
+        :param opcode:
+        :return:
+        """
         cmd = opcode.emit_command(opcode)
         if cmd:
             yield from cmd
@@ -39,7 +52,4 @@ class Machine:
             yield from data
 
         # Update changes in memory map, if any
-        opcode.apply(self)
-
-        # Tick 6502 CPU
-        self.cycle_counter.tick(opcode.cycles)
+        opcode.apply(self)

transcoder/opcodes.py

@@ -20,7 +20,6 @@ OpcodeCommand = enum.Enum("OpcodeCommand", _op_cmds)
 
 class Opcode:
     COMMAND = None  # type: OpcodeCommand
-    _CYCLES = None  # type: int
 
     # Offset of start byte in decoder opcode
     _START = None  # type: int
@@ -37,10 +36,6 @@ class Opcode:
     def __data_eq__(self, other):
         raise NotImplementedError
 
-    @property
-    def cycles(self) -> int:
-        return self._CYCLES
-
     @staticmethod
     def emit_command(opcode: "Opcode") -> Iterator[int]:
         # Emit address of next opcode
@@ -56,7 +51,6 @@ class Opcode:
 
 class Nop(Opcode):
     COMMAND = OpcodeCommand.NOP
-    _CYCLES = 11  # TODO: count
 
     def __data_eq__(self, other):
         return True
@@ -64,7 +58,6 @@ class Nop(Opcode):
 
 class Terminate(Opcode):
     COMMAND = OpcodeCommand.TERMINATE
-    _CYCLES = 6  # TODO: count
 
     def __data_eq__(self, other):
         return True
@@ -72,7 +65,6 @@ class Terminate(Opcode):
 
 class Ack(Opcode):
     COMMAND = OpcodeCommand.ACK
-    _CYCLES = 100  # TODO: count
 
     def emit_data(self) -> Iterator[int]:
         # Dummy bytes to pad out TCP frame
@@ -84,8 +76,6 @@ class Ack(Opcode):
 
 
 class BaseTick(Opcode):
-    _CYCLES = 73
-
     def __init__(self, content: int, offsets: Tuple):
         self.content = content
         if len(offsets) != 4: